Hi Biju,
On Thu, Apr 20, 2023 at 8:16 PM Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > -----Original Message-----
> > From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> > Sent: Thursday, April 20, 2023 6:15 PM
> > To: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> > Cc: Rob Herring <robh+dt@xxxxxxxxxx>; Krzysztof Kozlowski
> > <krzysztof.kozlowski+dt@xxxxxxxxxx>; Magnus Damm <magnus.damm@xxxxxxxxx>;
> > linux-renesas-soc@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; Prabhakar
> > Mahadev Lad <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> > Subject: Re: [PATCH 3/3] arm64: dts: renesas: rzg2l-smarc: Enable MTU3a
> > counter using DT overlay
> >
> > Hi Biju,
> >
> > On Thu, Apr 20, 2023 at 5:49 PM Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > > > -----Original Message-----
> > > > From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> > > > Sent: Thursday, April 20, 2023 4:40 PM
> > > > To: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> > > > Cc: Rob Herring <robh+dt@xxxxxxxxxx>; Krzysztof Kozlowski
> > > > <krzysztof.kozlowski+dt@xxxxxxxxxx>; Geert Uytterhoeven
> > > > <geert+renesas@xxxxxxxxx>; Magnus Damm <magnus.damm@xxxxxxxxx>;
> > > > linux- renesas-soc@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
> > > > Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> > > > Subject: Re: [PATCH 3/3] arm64: dts: renesas: rzg2l-smarc: Enable
> > > > MTU3a counter using DT overlay
> > > >
> > > > Hi Biju,
> > > >
> > > > On Mon, Apr 17, 2023 at 11:02 AM Biju Das
> > > > <biju.das.jz@xxxxxxxxxxxxxx>
> > > > wrote:
> > > > > Enable mtu3 node using dt overlay and disable scif2 node and
> > > > > delete {sd1_mux,sd1_mux_uhs} nodes as the pins are shared with
> > > > > mtu3 external clock input pins and Z phase signal(MTIOC1A).
> > > > >
> > > > > Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> >
> > > > > --- /dev/null
> > > > > +++ b/arch/arm64/boot/dts/renesas/rzg2l-smarc-pmod.dtso
> > > > > @@ -0,0 +1,43 @@
> > > > > +// SPDX-License-Identifier: GPL-2.0
> > > > > +/*
> > > > > + * Device Tree Source for the RZ/{G2L,V2L} SMARC EVK PMOD parts
> > > > > + *
> > > > > + * Copyright (C) 2023 Renesas Electronics Corp.
> > > > > + */
> > > > > +
> > > > > +/dts-v1/;
> > > > > +/plugin/;
> > > > > +
> > > > > +#include <dt-bindings/pinctrl/rzg2l-pinctrl.h>
> > > > > +
> > > > > +&mtu3 {
> > > > > + pinctrl-0 = <&mtu3_pins>;
> > > > > + pinctrl-names = "default";
> > > > > +
> > > > > + status = "okay";
> > > > > +};
> > > > > +
> > > > > +&pinctrl {
> > > > > + mtu3_pins: mtu3 {
> > > > > + mtu3-zphase-clk {
> > > > > + pinmux = <RZG2L_PORT_PINMUX(19, 0, 3)>; /*
> > > > > +MTIOC1A
> > > > */
> > > > > + };
> > > >
> > > > Unless I'm missing something, this signal is not available on the
> > > > PMOD connector?
> > >
> > > Yes, it is not available on the PMOD connector. SD card detection
> > > signal, is muxed with MTIOC1A (Z Phase signal). So for counter use
> > > case, we use it as MTIOC1A pins.
> >
> > As the signal is not available on the PMOD connector, can't you just ignore
> > the Z Phase signal, and keep the SD card CD signal available instead?
>
>
> Some customers are using Z phase signal in their product to clear the counter.
> Maybe we define a macro in overlay, by default Z phase signal is disabled.
>
> Is it ok?
>
> Note:-
> I use SD card removal/insert which changes the Z phase signal level for
> clearing the counter.
After giving this some more thought, I don't think this overlay belongs
upstream: it does not just enable hardware support, but provides a
way to test hardware, by redefining the meaning of signals on the
PMOD interface.
Do you agree?
I can add (a future version of) the overlay file (without the build
glue) to my topic/renesas-overlays branch[1], though.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git/log/?h=topic/renesas-overlays
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
